Wednesday's decision marks the twelfth, and possibly final, parole hearing for the 77-year-old Manson who will not be eligible for parole for another 15 years.
"This panel can find nothing good as far as suitability factors go," John Peck, a panel member, said.
"It's obvious from everything in the record that Mr Manson remains a danger to the public," said Deputy District Attorney Patrick Sequeira, who argued against the parole.
The parole board ruled Manson, who did not attend the hearing, had shown no signs of an effort to rehabilitate himself.
A recent damning statement made by the now grey-haired serial killer to a prison psychologist played a central role in the board's 20-minute delibertation.
'I'm special'
"I'm special. I'm not like the average inmate. I have spent my life in prison. I have put five people in the grave. I am a very dangerous man," Peck read aloud, quoting Manson from the prison transcripts.
Manson orchestrated a series of gruesome murders carried out by the so-called "Manson family", that terrified Los
Angeles 40 years ago.
Manson and his followers were convicted in the 1969 killings of actress Sharon Tate, then wife of director Roman Polanski, and four others.
Manson himself, serving as the leader of his "family", was convicted of murder at his instruction through the joint responsibility rule, making each member of a conspiracy guilty of crimes their fellow conspirators commit.
No clear motive was ever established for the murders.
Manson was sentenced to death, but his life was spared when the California supreme court briefly outlawed the death penalty in 1972.
"I'm done with him," Debra Tate, the sister of the actress, said following the hearing.
'No one was safe'
Under the law, inmates can be denied the chance to reapply for parole for up to 15 years.
Even Manson's state-appointed attorney, DeJon Lewis, found it difficult to argue for a client who had refused to meet with him. He said at the hearing that Manson should be in a hospital, but acknowledged the terror his client caused.
"The murders showed us that anyone could be killed at any time, and no one was safe, not even at home," Lewis said.
Manson would be 92 before he gets another opportunity to make his case.
Authorities read a litany of Manson's prison infractions, including the latest the manufacture and possession of a weapon, for which he is serving 15 months in an isolation unit.
